Lens array sheet and transmission screen and rear projection type display

ABSTRACT

A lens array sheet, a transparent screen using the same, and a rear-projection display device are provided in which it is possible to control a perspective angle for the image in both a horizontal direction and a vertical direction without causing a problem in that a gain (brightness) of a light is reduced by an optical absorption and an S/N ratio is reduced by an increased white dispersion.  
     A first lens array  18  and a second lens array 20 which are formed by disposing a plurality of half-cylindrical lenses  17, 19  in parallel on a common plain (a surface of a base member layer  13   a ) such that longitudinal directions of the cylindrical lenses  17, 19  should be orthogonal to each other. Unified lens array layer  13   b  and a shading layer 16 in which a section through which a light does not transmit is formed on a focal plain of the lens array layer  13   b  form a lens array sheet. Furthermore, fresnel lens are combined so as to form a transparent screen.

TECHNICAL FIELD

The present invention relates to a projection display such as aprojection television and display. In particular, the present inventionrelates to a lens array sheet which is suitable for such a usage and aprojection screen which uses such a lens array sheet.

It is possible to name a CRT, LCD (liquid crystal display device), DMD(Digital Micro-mirror Device; a trademark registered by TexasInstruments Corp.) for such a representative display such as aprojection television in which an image which is emitted from aprojector which is provided with various optical engine. In particular,a transparent (projection type, rear-projection type, rear type)projection television is representative.

Hereinafter, the present invention is explained for mainly a transparentprojection screen.

BACKGROUND ART

A screen is commonly known which is used for a projection televisionwhich is provided with a CRT projector having a structure shown in FIG.10 for one of a conventional projection television screen.

Such a screen is provided with a lentiular sheet 320 which has concavesections and convex sections for forming lens sections on it bothsurfaces and two pieces of lens sheet member for a fresnel lens sheet310 such that the lenticular sheet 320 is disposed nearer to anobserving person than the fresnel lens sheet 310.

Also, there is a case in which a plain protecting board (not shown indrawings) may be disposed on an outermost position near the observingperson. The lenticular sheet 320 is formed by forming lens sections 322,328 which are formed by disposing a plurality of cylindrical lens ofwhich vertical direction is its longitudinal direction in a horizontaldirection on both surfaces of the lenticular sheet 320.

The lenticular sheet 320 has a lens section 328 for the observing personso as to adjust a color shift for an image light which is emitted from athree-tube projector which has colors such as R, G, and B by refractingand dispersing the image light and a lens section 322 near an emittingside compatibly. (Hereinafter, it may be called a double-surfacelenticular sheet.)

It is common that the double-surface lenticular sheet 320 should beformed by an extruding method in which optical axes of the lens sectionson both surfaces must be aligned.

On the other hand, not only a refracting and dispersing function in ahorizontal direction by the above lens section (an image light isbroadened in a horizontal direction by disposing the cylindrical lensgroup in the horizontal direction) but also a broadening function forthe display image in also a vertical direction (enlarging a verticalperspective angle) are required in the projection screen.

An angle which is greater than 10 (ten) degree is required for a examplefor enlarging a vertical perspective angle (an angle which transmitsfrom an orthogonal direction to a front surface=screen in a case inwhich a brightness of the displayed image light in the front surface maybe reduced by a half when a viewpoint is moved from the front surface toan orthogonal direction) in a wide range.

Also, it is required in the projection screen that the displayed imagelight should be viewed in a high contrast. Also, it is necessary that aperipheral light other than the displayed image light should bereflected on the surface of the screen so as not disturb the observationand a shading layer 325 should be formed which is formed by a blackstripe (BS) which corresponds to a non-light-condensing section in thecylindrical lens (that is, such as a non-transparent section for theimage light) so as to have a smaller numerator in the aboverelationship.

As explained above, the double-surface lenticular sheet 320 is used fora projection television which is provided with a plurality of CRTprojectors (in general, three sets such as R, G, and B).

On the other hand, there is a projection television which has only oneset of projector (that is, a full-color display image is projected froma single lens) which is employs a method in which an LCD or a DMD isused for an optical engine section in the projector.

It is not necessary to compensate a color depositioned condition (colorshift) of the image light for the R, G, and B in the screen for theprojection-type projection television which has a single projector(which is called as a single-tube type). That is, it is acceptable onlyif the lens section which is formed by a cylindrical lens group shouldbe disposed on a surface of the lens sheet because only emitting range(perspective angle) for the image light should be broadened (such astructure is called a single-surface lenticular sheet).

FIG. 11 is a view for explaining an example for a structure for atransparent screen which is used for a single-tube projectiontelevision.

Basically, the transparent screen formed by two members such as alenticular sheet 370 and a fresnel lens sheet 360.

A lens section 71 is formed on only a surface of the lenticular sheet370. Also, a shading layer 375 is formed on a plain surface on which thelens section 371 is not formed.

For a case of a screen which is provided with a single-surfacelenticular sheet, it is required that the perspective angle should beenlarged in vertical direction as similarly to the above explaineddouble-surface lenticular sheet.

FIG. 5 is a detailed view for an example of a structure for aconventional transparent screen which is used for a liquid crystalprojection television etc. In the drawing, reference numeral 1 indicatesa fresnel lens. The fresnel lens 1 is formed by disposing a lens layer 1b which has convex sections and concave sections on a surface of a platebase member layer 1 a concentrically. Generally, the projector isdisposed near the base member layer 1 a in the liquid crystal projectiontelevision.

In addition, a lenticular sheet 2 is disposed near the lens layer 1 b inthe fresnel lens 1; thus, the transparent screen is formed by thefresnel lens 1 and the lenticular sheet 2.

For example, a structure of the lenticular sheet 2 is generally formedby a lenticular layer 3, a photo-sensitive resin layer 5, a shadinglayer 6, a bonding agent layer 7, and a dispersing layer 8 in which thelenticular layer 3 is disposed in the fresnel lens 1 and the dispersinglayer 8 is disposed near the observing person. Here, a hard coat layer 9is disposed on a surface of the dispersing layer 8 which is near theobserving person according necessity so as to protect the surface.

The lenticular layer 3 is formed a plate base member layer 3 a and alens layer 3 b which is disposed on its surface. The lens layer 3 b isformed by disposing a plurality of half-cylindrical lenses 4 such thatthe longitudinal direction should be in parallel and a cylindricalsurface 4 a should be disposed near the fresnel lens 1.

Hereinafter, an example for a manufacturing operation for the structureof the lenticular sheet 2 is explained.

For manufacturing the lenticular layer 3, a lenticular layer 3 b isformed by disposing a radiation curable resin under a non-hardenedcondition between a surface of the base member layer 3 a and a mold(stamper) which has a reverse shape of the lens layer 3 b, emitting apredetermined radiation from other surface of the base member layer 3 a,and hardening the above resin. Also, the above lens layer 3 b is bondedon the base member layer 3 a; thus, a lenticular layer 3 is obtained.

Next, a photo-sensitive resin layer 5 is applied on a surface of thelenticular layer 3 near the base member layer 3 a.

For such a photo-sensitive resin layer 5, it is possible to name amember which has a characteristic in which it is adhesive undernon-exposed condition and the adhesiveness disappears after beingexposed and degenerated.

In addition, when a light is emitted from the lens array 3 b via thefresnel lens 1 as similar to a case in which the transparent screen isused, a beam in a stripe manner is emitted so as to be condensed on thephoto-sensitive resin layer 5 via the lenticular layer 3. In addition,the photo-sensitive resin layer 5 in a section which is exposed isdenatured; thus the adhesiveness disappears. In addition, atranscription film which has a black transcription layer such as a blackcarbon is pressed on the photo-sensitive resin layer 5, thetranscription layer is transcribed on an unexposed section which has anadhesiveness; thus, a shading layer 6 in a stripe manner in which aplurality of black lines are disposed is formed.

That is, a light is shaded by the shading layer 6 in a section throughwhich the light does not transmit.

After that, plate dispersing layer 8 is further layered via a filmadhesive layer 7 so as to be unified tightly; by doing this, alenticular sheet 2 is obtained. Here, the dispersing layer 8 is formedby mixing a dispersing member which is formed by a plurality of glassbeads in a matrix which is made of a plastic member such as an acrylicmember.

In addition, a hard coat layer 9 is layered on a surface of thedispersing layer 8 according to necessity so as to be unified.

In addition, if the transparent screen is attached to a liquid crystalprojector which is provided with a projector as shown in FIG. 5 and thelight is emitted from the projector, the light becomes an approximateparallel light via the fresnel lens 1. In addition, a predeterminedoptical distribution angle is added by transmitting the light throughthe lenticular layer 3 such that the light disperses in a horizontaldirection in the image appropriately; thus, the perspective angle iscontrolled in this direction. Here, the light which transmits throughthe lenticular layer 3 becomes a stripe light which is parallel with alongitudinal direction of the cylindrical lens. Furthermore, a lightdisperses in a vertical direction appropriately by the function of thedispersing layer 8 via the shading layer 6; thus, the perspective angleis controlled in this direction. Here, it is possible to improve S/Nration by the shading layer 6; thus, it is possible to provide an imagewhich has a desirable contrast.

As explained above, a lenticular layer and a dispersing layer are usedin a combined manner so as to control the perspective angle of the imagein a horizontal direction and a vertical direction in a conventionallenticular sheet and a transparent screen. However, there have beenproblems such as a reduced gain (brightness) which is caused by a lightabsorption in the dispersing layer and a reduced S/N ration caused bythe increase in a white dispersion.

Also, a method can be provided for controlling the perspective angle inthe horizontal direction and the vertical direction by disposing thecylindrical lenses such that each longitudinal direction should beorthogonal to each other on both sides when two pieces of lenticularsheets are overlapped such that each longitudinal direction should beorthogonal to each other or a plurality of the cylindrical lenses aredisposed on both surfaces of a base member layer.

However, in the former case, it is necessary to control the relationshipof two lenticular sheets strictly so as to maintain the opticalcharacteristics in two lenticular sheets. Also, it is necessary to forma lens in a fine forming operations under condition that it is necessaryto used the material member for forming the cylindrical lens twice asmany as the conventional case substantially; therefore, there has been aproblem that the cost for the material member and the cost for formingthe material member are expensive.

In a latter case, the cylindrical lens groups of which dispositiondirection are different from each other must be formed on both surfacesof one piece of the base material layer. Therefore, as similarly, it isnecessary to perform the forming operations for the lens section twice.

Furthermore, there is a method in which a plurality of independentlenses or prisms which can add the distribution angle in both thevertical direction and the horizontal direction are disposed on asurface of the base member layer as similar to a micro-lens array.However, it is necessary to perform a complicate forming operation andit is difficult to increase an area and perform a fine pitch operation.Also, productivity is low. Therefore, the cost increases inevitably.

Furthermore, in Japanese Unexamined Patent Application, FirstPublication No.

Hei 9-311203, a lenticular lens sheet is disclosed is disclosed whichforms a lens plate in which a plurality of lenticular lens elements(cylindrical lenses) which have lenticular lens shape on incidentsurface and fine lenticular lens shapes which are formed by a moldingoperation so as to be orthogonal with each other along surfaces of thecylindrical lenses.

As explained above, there is a problem to be solved in the transparentprojection television for enlarging the perspective angle in thevertical direction and improving the contrast.

A dispersing layer which is formed by dispersing the optical dispersingparticle and lenticular layer are used in a combined manner so as tocontrol the perspective angle of the image in a horizontal direction anda vertical direction in a conventional lenticular sheet and atransparent screen.

However, in the above optical dispersing layer, if an optical dispersingagent (particle) is used excessively, there have been problems in that again (brightness) is reduced by an optical absorption and an S/N rationis reduced by an increase in a white dispersion.

Also, a diameter of a projection pupil in a projection lens is small inthe transparent projection television which is provided with a liquidcrystal projector. Therefore, as compared with a CRT transparentprojection television, there have been inherent problems in that thebrightness of the incident light from the projector is partially high(hot spot), the cylindrical lens may be observed to be bright in astripe manner in a disposing direction (hot bar), and an unnecessaryscintillation which is observed in a projection image may occurfrequently.

Furthermore, it is not possible to solve these problems sufficientlyonly by enlarging the perspective angle in the vertical direction, a hotspot, a hot bar, and a scintillation by enhancing the optical dispersioncharacteristics by using an optical dispersing agent (particle). Thatis, it is newly required to add a dispersion angle by a lens function.

DISCLOSURE OF INVENTION

The present invention was made in consideration of the above problems.An object of the present invention is to provided a transparent screenin which there are fewer optical absorption and reduction in the gain(brightness) so as to restrict the white dispersion.

Furthermore, another object is to provide a transparent screen of whichproduction cost is cheap.

In order to solve the above problems, the invention of a first aspect ofthe present invention is a lens array sheet which is provided with alens array layer which has a unified lens array wherein first lensarrays and second lens arrays which are formed by disposing a pluralityof half-cylindrical lenses are disposed so as to cross each otherorthogonally on a common plain.

The invention of a second aspect of the present invention is a lensarray sheet in which the first lens array is as high as the second lensarray.

The invention of a third aspect of the present invention is a lens arraysheet in which the height of the first lens is different from the heightof the second lens array.

The invention of a fourth aspect of the present invention is a lensarray sheet in which shading sections for shading a transmitting lightare provided on a focal plain of the lens array layer.

The invention of a fifth aspect of the present invention is a lens arraysheet in which a cross section of the cylindrical lens is aspherical.

The invention of a sixth aspect of the present invention is a lens arraysheet in which the lens array layer is formed by a base material layerand a lens layer which is disposed on a surface of the lens array layer,and the lens layer is formed by a radiation curable resin.

The invention of a seventh aspect of the present invention is atransparent screen which is provided with a lens array sheet accordingto any one of the first to fourth aspects.

The invention of an eighth aspect of the present invention is atransparent screen according to the fifth aspect in which the fresnellens is formed by a base material layer and a lens layer which is formedon a surface of the fresnel lens layer is formed by a radiation curableresin.

The invention of a ninth aspect of the present invention is arear-projection display device according to the seventh aspect or theeighth aspect further comprising the transparent screen.

The invention of a tenth aspect of the present invention is a lens arraysheet in which a first lens array which is formed by half-cylindricallenses in parallel and half-cylindrical lenses which is formed byhalf-cylindrical lenses in parallel are disposed on a same plain suchthat longitudinal directions of the cylindrical lenses are orthogonal,the lens array is provided with a lens array layer which has a unifiedlens layer, and a plurality of cylindrical lenses are disposed so as tohave intervals in parallel in either one of the first lens array or thesecond lens array.

In the invention of an eleventh aspect of the present invention, avalley section in the first valley section and a valley section in thesecond lens array may be disposed so as to coincide with each other.

Also, as a twelfth aspect of the present invention, it may be acceptableif a shading layer is provided on a focal plane of the lens array so asto block the transmitting light.

In a thirteenth aspect of the present invention is a lens array sheetany one of the tenth aspect to twelfth aspect in which a plurality ofcylindrical lenses are disposed in parallel without intervals in eitherone of the first lens array or the second lens array in which aplurality of cylindrical lenses are disposed in parallel with intervals.

Furthermore, in a lens array sheet of a fourteenth aspect of the presentinvention, it is acceptable if the cross section of the cylindrical lensin the first lens array may be aspherical in the lens array sheet.

Also, as a fifteenth aspect of the present invention, it is acceptableif the lens array layer is disposed on a surface of the base materiallayer and the lens array layer is formed by a radiation curable resin.

Also, as a sixteenth aspect of the present invention, a rear-projectiondisplay device which is provided with the above aspect of thetransparent screen is provided.

Also, as a seventeenth aspect of the present invention, a lens arraysheet is provided in which a first cylindrical lens which is formed bydisposing a plurality of half-cylindrical lenses in parallel and asecond lens array which is formed by disposing a plurality ofhalf-cylindrical lenses in parallel are disposed on a same plain so asto be orthogonally approximately in longitudinal directions of thecylindrical lens in a lens array layer which has a unified lens layer, apeak of unit lens in the first lens array is continuous over thelongitudinal direction, the second lens array is disposed by forming theunit lenses the peak of which is not continuous over a longitudinaldirection between the peaks of the neighboring unit lenses in the firstlens array.

Also, an eighteenth aspect of the present invention is a transparentscreen which is provided with the above lens array sheet.

Furthermore, as a nineteenth aspect of the present invention, thetransparent screen of the present invention can be formed by the abovelens sheet and the fresnel lens.

In the twentieth aspect of the present invention, a lens array sheetwhich is provided with a lens array layer which has a unified lens layer(hereinafter called an orthogonal lens section) is employed in which twolenticular sheets are not layered so as to be orthogonal in thelongitudinal direction of the cylindrical lenses, nor the cylindricallenses are disposed on both surfaces of the base member layer so as tobe orthogonal in the longitudinal direction. Instead, the first lensarray and the second lens array are disposed so as to be approximatelyorthogonal in the longitudinal direction of the cylindrical lenses ononly one surface of a piece of the lens sheet.

In a lens array sheet according to a twenty-first aspect of the presentinvention, a first cylindrical lens which is formed by disposing aplurality of half-cylindrical lenses in parallel and a second lens arraywhich is formed by disposing a plurality of half-cylindrical lenses inparallel are disposed on a same plain so as to be orthogonallyapproximately in longitudinal directions of the cylindrical lens in alens array layer which has a unified lens layer, a peak of unit lens inthe first lens array is continuous over the longitudinal direction, andthe second lens array is disposed by forming the unit lenses the peak ofwhich is not continuous over a longitudinal direction between the peaksof the neighboring unit lenses in the first lens array.

In a twenty-second aspect of the present invention, at least the firstlens array or the second lens array may be disposed in parallel via aplain section between the unit lenses. Also, it may be acceptable if theunit lenses are disposed without intervals therebetween.

In a twenty-third aspect of the present invention, the opticaldistribution characteristics (dispersion characteristics) may bedesigned differently in the unit lens in the first lens array and thesecond lens array.

In a twenty-fourth aspect of the present invention, the feature of thepresent invention which is designed for a suitable screen is that thefirst lens array is a lenticula (horizontal lenticular) which is formedby disposing cylindrical lens group in a horizontal direction so as tohave a dispersing (distributing) characteristics in a horizontaldirection, the second lens array is a lenticular (vertical lenticular)which is formed by disposing the cylindrical lens group in the verticaldirection so as to have a vertical dispersing (distributing)characteristic. A relationship such as dispersion characteristics by thefirst lens array>dispersion characteristics by the second lens array iseffective. Also, a half angle aV (a measured angle in which a brightnessof an emitted light which is measured orthogonally from a front surfaceto a lens array sheet is as a half as the half angle which is measuredin an offset manner from the orthogonal condition) in the second lensarray in a vertical direction is not fewer than 10 degree, and aperspective angle dV (a measured angle in which a brightness of anemitted light which is measured orthogonally from a front surface to alens array sheet is as a twentieth half as the perspective angle whichis measured in an offset manner from the orthogonal condition) in thesecond lens array in a vertical direction is not fewer than 35 degree.

In a twenty-fifth aspect of the present invention, the lens layer of thelens array sheet and an opposite surface are plain surfaces, and ashading layer is formed on the plain surface to which a light is notcondensed by the lens layer.

In a twenty-sixth aspect of the present invention, the shading layer isformed by an aperture section which is continuous in a stripe manneraccording to the first lens array and an aperture section which is notcontinuous in an approximate spot manner according to the second lensarray (each spot is in a stripe manner according to a light condensingsection in the cylindrical lens).

A ratio of the shading layer on the plain surface is suitable between30% and 90%.

Also, in a twenty-seventh aspect of the present invention, it ispreferable to form a lens layer by a hardened product of radiationcurable resin on a surface of a plain base member which is formed byradiation transmittable base material for a fine pitch lens array.

In a twenty-eighth aspect of the present invention, the above lens arraysheet is combined with a fresnel lens sheet which has a function foremitting the projection light from the projector in an approximateparallel light so as to form a transparent projection screen.

In a twenty-ninth aspect of the present invention, the opticaldispersing layer which is formed by dispersing the optical dispersingparticle is formed in at least any section of the fresnel lens sheet andthe lens array sheet for a common example for the transparent projectionscreen.

In a thirtieth aspect of the present invention, a shading pattern (blackmatrix=BM) is formed according to a “self-alignment method” in which alight condensing section/non-light condensing section forms an aperturesection/shading section according to a light condensing characteristicsin the lens itself so as to realize a high shading ratio; thus, it isadvantageous for improving the contrast.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross section for a lens array layer and a shading layerwhich form an example for a lens array sheet of the present invention.

FIG. 2 is an isometric view for the lens array layer shown in FIG. 1.

FIG. 3 is an isometric view for a cross section in which a part of thelens array layer shown in FIG. 2 is cut.

FIG. 4 is plan view for an example of a focusing pattern in the lensarray shown in FIGS. 1 to 3.

FIG. 5 is a view for a general structure of an example for aconventional transparent screen.

FIG. 6 is an isometric view for an embodiment of a lens array sheetaccording to the present invention.

FIG. 7 is a general view for a cross section for the lens array sheet.

FIG. 8 is an enlarged general view for a cross section for the lensarray sheet.

FIG. 9 is an isometric view for another embodiment of a lens array sheetaccording to the present invention.

FIG. 10 is a view for explaining an example for a conventionalprojection screen.

FIG. 11 is a view for explaining an example for a conventionalprojection screen.

FIG. 12 is a view for explaining an example for a projection screenaccording to the present invention.

FIGS. 13A and 13B are views for explaining examples for a structure ofan orthogonal lens section.

FIG. 14 is a view for explaining an example for a structure of theshading layer.

FIG. 15 is a table for a comparison between the present invention and acomparative example with regard to an optical characteristic(perspective view characteristic).

FIG. 16 is a table for a comparison between the present invention and acomparative example with regard to an optical characteristic (contrast).

FIG. 17 is a rear-projection display device which is provided with atransparent screen which uses the lens array sheet of the presentinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment

FIG. 1 is a cross section which shows a lens array layer and a shadinglayer which form an example for a lens array sheet according to thepresent invention. FIG. 2 is an isometric view for showing the lensarray layer. FIG. 3 is an isometric view showing a cross section whichis viewed by cutting a part of the lens array layer shown in FIG. 2.Here, the lens shapes for the lens array sheet shown in FIGS. 1 to 3 aredesigned. FIGS. 1 to 3 are drawn actually according to the designedshape.

A main feature for this lens array sheet is a lens array layer 13. Thelens array layer 13 is formed a plate base member layer 13 a and a lenslayer 13 b which is disposed on its surface.

The lens layer 13 b is formed by a lens array 18 in which a plurality ofhalf-cylindrical lenses 17 are disposed in parallel which are providedwith a cylindrical surface 17 on a surface of a lens and a plain 17 b onother surface such that the longitudinal directions, and a second lensarray 20 which is formed by similarly disposing a plurality ofcylindrical lenses 19 which are provided with a cylindrical surface 19 aand a plain 19 b such that the longitudinal directions are parallel.

Here, the cross section of the cylindrical lenses 17, 19 are notcompletely cylindrical (spherical lens). It is possible to use acommonly known non-half-circular shape (such as a second dimensionalaspherical shape) such as a half-oval shape (oval surface lens), aparabolic shape (parabolic surface lens). Furthermore, it is possible touse a highly dimensional aspherical shape which has an item which isgreater than a second dimension. It is possible to reduce an aberrationfor focusing an image when an aspherical lens is used; thus, it ispossible to form an incident light in a fine pitch.

The plains 17 b, 19 b of the first lens array 18 and the second lensarray 20 are disposed on a common plain (a surface of the base memberlayer 13 a) such that the longitudinal direction of the cylindrical lens17 which forms this and the longitudinal direction of the cylindricallens 19 should be orthogonal so as to form a lens layer 13 a.

The cylindrical lens 17 and the cylindrical lens 19 are orthogonallycross crossing section 21 such that each of them engage with each other.Here, actually, the cylindrical lenses 17, 17 . . . and the cylindricallenses 19, 19 . . . are molded unitarily; thus, the lens array layer 13is formed by a piece of member.

For a member to form the lens array layer 13, it is possible to use anymember limitlessly as long as it can be used for an optical memberbecause it is a transparent member such as a glass member or a plasticmember. It is preferable to use a plastic member if a manufacturingefficiency is taken into account. For a plastic member, it is possibleto name an acrylic resin such as poly(methyl methacrylate), apolycarbonate, an copolymer of acryl-stylene, a Stylene resin, and aPoly (vinyl chloride). Also, it is preferable to use a radiation curableresin such as an ultraviolet-ray curable resin or an electronic beamcurable resin for a member for forming the lens layer 13 b because it ispossible to form a fine pitch. For such a radiation curable resin, forexample, it is possible to use a composition which is formed by doping areaction diluting agent, a light polymerization starting agent, and anphotosensitizer to a urethane(meta)acrylate and/or anepoxy(meta)acrylateoligomer. For such an urethane(meta)acrylateoligomer,it is not limited in particular. For example, it is possible to obtainby reacting polyols such as an ethyleneglycol, 1,4 butanediol,neopentylglycol, polycaprolactonepolyol, polyesterpolyol,polycarbonatediol, and poly(tetramethylene glycol) with a polyisocyanatesuch as hexamethylene diisocyanate, isophorone diisocyanate, toluenediisocyanate, and xylene diisocyanate. For such anepoxy(meta)acrylateoligomer, it is not limited in particular.

For example, it is possible to obtain by reacting a (meta)acrylic acidwith an epoxy resin such as bisphenol A epoxy resin, bisphenol A epoxyresin, phenolnovolac type epocy resin, terminal glycidyl ether of anadditional bishenol A propylene oxide, and a fluorene epoxy resin.

It is possible to manufacture the lens array layer 13, for example, by afollowing manner. That is, the lens layer 13 b is formed by applying aradiation curable resin under non-hardened condition on the base memberlayer 13 a which is formed by a plastic member such a poly(ethyleneterephthalate), polycarbonate, and vinyl chloride, compressing a moldingstamper on a surface thereon, and emitting a predetermined radiation soas to harden.

It is possible to manufacture the molding stamper, for example, by afollowing manner. That is, during manufacturing a molding stamper formolding a conventional lenticular, for example, a cutting section isformed on a surface of a cylindrical cylinder of which surface is madeof a copper in a circular direction of the cylinder by using a cuttingbype which has a corresponding shape to a unit lens which is supposed tobe manufactured. Such cutting sections are formed in a plurality ofsections in parallel, it is possible to obtain a stamper for lenticular.Furthermore, if the cutting sections are formed in a plurality ofsections in parallel in an orthogonal direction to the cutting sectionin the circular direction, it is possible to obtain a molding stamperwhich is used for manufacturing the lens array layer 13 of the presentinvention.

Therefore, it is possible to manufacture the molding stamper formanufacturing the lens array layer 13 of the present invention by usinga conventional technology easily; thus, the productivity is desirable.

In this way, it is possible to manufacture the lens array layer 13according to a method which is similar to the method which is used formanufacturing a conventional lenticularl.

Also, as shown in FIG. 1, a photo-sensitive resin layer 15 and further ashading layer 16 are disposed on other surface (focal plane) of the basemember layer 13 a.

The photo-sensitive resin layer 15 and the shading layer 16 aremanufactured in following manner. That is, as shown in FIG. 5, thephoto-sensitive resin layer 15 in a section which is exposed through thelens array layer 13 is denatured by disposing the fresnel lens 1 inparallel under condition that the fresnel lens 1 should be used for atransparent screen actually and emitting a light from the lens layer 13b via the fresnel lens 1; thus, the adhesiveness disappears. Inaddition, a transcription film which has a black transcription layersuch as a black carbon is pressed on the photo-sensitive resin layer 15,the transcription layer is transcribed on an unexposed section which hasan adhesiveness; thus, a shading layer 16 is formed.

Here, the shading layer in the present invention is not limited to theabove structure. In addition, following structure is preferable.

-   (1) a black toner in place of a transcription layer is applied in a    section in which an adhesiveness of the above photosensitive resin    layer 15 is maintained-   (2) a black photosensitive resin layer is formed (disposed) on an    entire focal plain of the base member layer 13 a, and after that the    photosensitive resin layer in the section which is exposed via the    lens array layer 13 is removed.-   (3) a silver halide is formed on an entire surface of a focal plain    of the base member layer 13 a such that the above layer which is    exposed through the lens array layer 13 should be transparent by a    developing process    As explained above, a structure is preferable in which an aperture    section/shading layer should be limited by using a so-called    self-alignment method.

In such a case, a matrix focusing pattern is formed by a first focusingpattern in a stripe manner by condensing a light by the cylindricallenses 17, 17 . . . (first lens array 18) and a second focusing patternin a stripe manner which is orthogonal to the first focusing pattern bycondensing a light by cylindrical lenses 19,19 . . . (second lens array20). That is, the perspective angles of the light which is emitted fromthe lens layer 13 b in both the vertical direction and the horizontaldirection are controlled in a single operation by the first lens array18 and the second lens array 20.

FIG. 4 shows an example for such a focusing pattern.

The shading layer 16 is formed so as to block a light which transmitsthrough the lens array layer 13 via the fresnel lens 1 in a section inwhich the light should not transmit therethrough. Therefore, a pluralityof approximate square shading sections 16 a. . . are disposed in boththe vertical direction and the horizontal direction in a predeterminedinterval respectively according to such a focusing pattern.

In addition, it is possible to form a lens array sheet by disposing anadhesive layer 7, a dispersing layer 8, and a hard coat layer 9 etc.according to necessity as shown in FIG. 5.

In this way, it is possible to control the optical distributioncharacteristics (perspective angle) of the light in both the verticaldirection and the horizontal direction which transmits the lens arraylayer 13 by the first lens array 18 and the second lens array 20 in thislens array sheet.

Therefore, it is possible to restrict a material cost and amanufacturing cost with compared to a case in which two layers such aslens array layers are used, or the lens layers are formed on bothsurfaces of the base member layer.

Also, it is possible to avoid the optical absorption by the dispersinglayer 8 and the reduction of the gain by omitting or simplifying thedispersing layer 8. As a result, it is possible to restrict a whitedispersion phenomenon which is caused by the dispersing layer 8 so as torealize a high S/N ratio.

Here, if the dispersing layer 8 is not formed, it is preferable to forma lens array sheet by disposing a hard coat layer 9 on the shading layer6.

Here, it is possible to modify a thickness of each layer in the lensarray sheet and a pitch of the lens layer 3 b according to the usageappropriately without being limited.

In addition, as shown in FIG. 5, it is possible to form the transparentscreen by disposing the lens array sheet of the present invention inplace of the lenticular sheet 2 and the fresnel lens 1.

Here, it is possible to use a commonly known member while the structureof the fresnel lens 1 is not limited in particular. It is preferable toform the lens layer 1 b by applying a Radiation curable resin under anon-hardened condition on the base member layer 1 a which is formed by aplastic member such as a poly(ethylene terephthalate), polycarbonate,poly (vinyl chloride) and compressing the molding stamper from thereonbecause it is possible to perform a fine molding operation so as toobtain fine-pitch product.

First Embodiment

Hereinafter, a first example of the present invention is shown so as toclarify an effect of the present invention.

As explained above, the lens shapes for the lens array sheet shown inFIGS. 1 to 3 are designed. FIGS. 1 to 3 are drawn actually according tothe designed shape.

In the present example, design parameters are determined as follows;thus, an experiment for proving the effect is performed.

(Design Parameters)

-   (1) In the base member layer for the lens array layer, a material    member is a Polyethylene terephthalate, and a thickness is 0.188 mm.-   (2) In the lens layer for the lens array layer, a material member is    an UV photosensitive resin. The lens is formed in an aspherical    shape which is formed by adding a higher dimension with reference to    a surface an oval surface which has 182 μm pitch.-   (3) Cromarin (a registered trademark for a product of DUPON) film    having 20 μm thickness is used for a photosensitive resin layer.

That is, a test piece which has 30 mm×30 mm size is produced accordingto such a design and an optical distribution characteristics isexamined. As a result, approximately 30 degrees of perspective angle(half angle) is realized both in an up-down direction (verticaldirection) and a left-right direction (horizontal direction). Thus, itis possible to realize a predetermined optical characteristics. Here,the perspective angle (half angle) indicates an angle which is a half ofbrightness in a front end of the lens array sheet.

Furthermore, it is observed that a focusing pattern in this lens arraylayer is similar to a focusing pattern which is shown in FIG. 4. Inaddition, when a light is emitted from a projector to a lens array sheeton which a shading layer is disposed so as to correspond to such afocusing pattern, there is no problem in transmitting the lighttherethrough.

In this way, it is possible to add perspective angles both in ahorizontal direction and a vertical direction in the lens array sheetaccording to the present example. Here, the perspective angle is addedin a conventional lenticular sheet only in a horizontal direction of thelens as explained above. Thus, it is not possible to add the perspectiveangle in a vertical direction. Therefore, in the present example, it isconfirmed that it is possible to realize a similar effect to aconventional case easily even if a dispersing member is omitted orreduced than in a conventional case. Therefore, it is confirmed that itis possible to realize a high quality image and a lower cost compatiblyeasily by the present invention.

Second Embodiment

Hereinafter, a detail of the second embodiment of the present inventionis explained with reference to drawings as follows.

FIGS. 6 and 7 show an example or the lens array sheet according to thepresent invention. FIG. 6 is an isometric view for the lens array sheet.FIG. 7 is a cross section.

FIG. 8 is a cross section for an important part of a prototype lensarray sheet which is produced in an embodiment of the present inventionwhich is explained later in an enlarged manner.

This lens array sheet 201 is formed by a base member layer 202 which isformed by a transparent material member, and a lens array layer 203which is disposed on a surface of the base material layer 202. A featureof the present invention resides in a structure of the lens array layer203.

In a structure of the above lens array layer 203, a first lens array 205which is formed by disposing a plurality of cylindrical lenses 204without intervals therebetween in parallel and a second lens array 207which is formed by disposing a plurality of cylindrical lenses 206 in adirection which is crossing, preferably orthogonal, to a longitudinaldirection of the first lens array 205 are disposed on a common surfaceof the base member layer 202.

A shading layer 211 is disposed on a surface which is opposite to thebase member layer 2 on which the lens array layer 203 is formed which isa focal plane of the lens array. The shading layer 211 is formed by aplurality of shading aperture sections 210 for through whichtransmitting the emitted light 213 when an incident light 212 transmitsthe lens array layer 203 so as to be emitted from the focal plane and ashading material member such as a shading layer shading section 209which is formed, for example, by a carbon black film which is disposedaround the shading layer aperture sections 210.

The cross sectional shape for the two cylindrical lenses 204, 206 whichform the first lens array 205 and the second lens array 207 is notlimited to spherical shape. It is possible to use a so called asphericalshape such as an oval surface, a parabolic surface (see cylindrical lens4 shown in FIG. 3). It is possible to reduce an aberration for focusingan image when an aspherical lens is used; thus, it is possible to forman incident light in a fine pitch.

For a member to form the lens array layer 203, it is possible to use anymember limitlessly as long as it can be used for an optical memberbecause it is a transparent member such as a glass member or a plasticmember. It is preferable to use a plastic member if a manufacturingefficiency is taken into account.

For a plastic member, it is possible to name an acrylic resin such aspoly(methyl methacrylate), a polycarbonate, an copolymer ofacryl-stylene, a Stylene resin, and a Poly (vinyl chloride).

Also, it is preferable to use a radiation curable resin such as anultraviolet-ray curable resin or an electronic beam curable resin for amember for forming the lens array layer 203 b because it is possible toform a fine pitch.

For such a radiation curable resin, for example, it is possible to use acomposition which is formed by doping a reaction diluting agent, a lightpolymerization starting agent, and an photosensitizer to aurethane(meta)acrylate and/or an epoxy(meta)acrylateoligomer. For suchan urethane(meta)oligomer, it is not limited in particular. For example,it is possible to obtain by reacting polyols such as an ethyleneglycol,1,4 butanediol, neopentylglycol, polycaprolactonepolyol,polyesterpolyol, polycarbonatediol, and poly(tetramethylene glycol) witha polyisocyanate such as hexamethylene diisocyanate, isophoronediisocyanate, toluene diisocyanate, and xylene diisocyanate. For such anepoxy(meta)acrylateoligomer, it is not limited in particular. Forexample, it is possible to obtain by reacting a (meta)acrylic acid withan epoxy resin such as bisphenol A epoxy resin, bisphenol A epoxy resin,phenolnovolac type epocy resin, terminal glycidyl ether of an additionalbishenol A propylene oxide, and a fluorene epoxy resin.

It is possible to manufacture the lens array layer 203, for example, bya following manner. A radiation curable resin is applied on the basemember layer 202 which is formed by a plastic member under unhardenedcondition. A molding stamper is compressed on the surface so as toperform a mold pressing operation. Simultaneously, a predeterminedradiation is emitted so as to harden it; thus, a lens array layer 203 ismolded.

The above explained molding stamper can form a lens layer, for example,in a following way. That is, during manufacturing a molding stamper formolding a conventional lenticular, for example, a cutting section isformed on a surface of a cylindrical cylinder of which surface is madeof a copper in a circular direction of the cylinder by using a cuttingbyte which has a round edge shape. Such cutting sections are formed in aplurality of sections in parallel, it is possible to obtain a stamperfor lenticular. Furthermore, a plurality of cutting sections are formedin a crossing direction, preferably in an orthogonal direction, to thecutting section in this circular direction, it is possible to obtain amolding stamper which can be used for manufacturing the lens array layer3 which is a characteristic part of the present invention.

Therefore, it is possible to manufacture the molding stamper formanufacturing the lens array layer 203 which is a characteristic part ofthe present invention by using a conventional technology easily; thus,the productivity is desirable. In this way, it is possible tomanufacture the lens array layer 1 according to a method which issimilar to the method which is used for manufacturing a conventionallenticular lens sheet.

It is possible to manufacture a photo-sensitive resin layer which formsthe lens array layer 203 and the shading layer 211 in a following way.If the fresnel lenses are disposed in parallel actually under a similarcondition in which they are used for the transparent screen and a lightis emitted from the lens layer of the lens array sheet via the fresnellens, the photo-sensitive resin layer in a part which is exposed byalilght which transmits the lens array layer 203 is denatured; thus, anadhesiveness disappears. In addition, a transcription film which has ablack transcription layer such as a black carbon is pressed on thephoto-sensitive resin layer, the transcription layer is transcribed onan unexposed section which has an adhesiveness; thus, a shading layer211 is formed.

In such a case, a focusing pattern in a ladder manner is formed by astripe first focusing pattern which is formed by condensing a light bythe cylindrical lens and a stripe second focusing pattern which isorthogonal to the first focusing pattern. That is, the perspectiveangles of the light which is emitted from the lens layer in both thevertical direction and the horizontal direction are controlled in asingle operation by the first lens array and the second lens array.

The shading layer 11 is disposed so as to block a light in a sectionthrough which the light does not transmit. Therefore, a plurality ofshading sections are disposed according to such a focusing patternregularly both in a vertical direction and a horizontal directionrespectively.

In addition, it is possible to form a lens array sheet by disposing anadhesive agent layer, a dispersing layer, and a hard coat layer etc. onthe shading layer according to necessity.

In this way, it is possible to control the optical distributioncharacteristics (perspective angle) of the light in both the verticaldirection and the horizontal direction which transmits the lens arraylayer 203 by the first lens array 205 and the second lens array 207 inthis lens array sheet 201.

Therefore, it is possible to restrict a material cost and amanufacturing cost with compared to a case in which two layers such aslens array layers are used, or the lens layers are formed on bothsurfaces of the base member layer.

Also, it is possible to avoid the optical absorption by the dispersinglayer and the reduction of the gain by omitting or simplifying thedispersing layer 8. As a result, it is possible to control a whitedispersion phenomenon which is caused by the dispersing layer 8 so as torealize a high S/N ratio.

Here, it is possible to modify a thickness of each layer in the lensarray sheet 201 and a pitch of the lens array layer 203 according to theusage appropriately without being limited.

FIG. 9 is a view for another embodiment of a lens array sheet accordingto the present invention. Also, the lens array sheet of the presentinvention is provided in which a first cylindrical lens which is formedby disposing a plurality of half-cylindrical lenses 204 in parallel anda second lens array which is formed by disposing a plurality ofhalf-cylindrical lenses 207 in parallel are disposed on a same plain soas to be orthogonally approximately in longitudinal directions of thecylindrical lens in a lens array layer which has a unified lens layer, apeak of unit lens in the first lens array is continuous over thelongitudinal direction, the second lens array is disposed by forming theunit lenses the peak of which is not continuous over a longitudinaldirection between the peaks of the neighboring unit lenses in the firstlens array. It is possible to realize an effect of the lens array sheetwhich is similar to the lens array sheet in the above explained firstembodiment.

Hereinafter, an effect of the present invention is explained withreference to a second example.

In the present example, design parameters a to g for the lens arraysheets 201 which is shown in FIG. 8 are determined as follows andexperiments are performed so as to prove the effects.

(Design Parameters)

For the base member layer for the lens array layer 203, the materialmember is a Polyethylene terephthalate. Its thickness d is 0.125 mm.

The material member for the cylindrical lens 4 for the lens array layer203 is a photo-sensitive resin layer. Interval a for the lenses is 0.252mm. A protruding height b is 0.08 mm. Width c for the lens is 0.168 mm.A surface shape is an aspherical to which a high dimension is added withreference to an oval surface. The cylindrical lens 6 in the second lensarray is formed such that an interval e between the lenses is 0.04079mm, a protruding height is 0.008 mm, a curvature f is 0.03 mm so as tobe a hemispherical shape.

For the photo-sensitive resin layer, a Cromarin film which is a positivephoto-sensitive resin adhesive layer of which adhesiveness disappears bybeing exposed to a light (a product of DUPON; trademark is registered)is used which has 20 μm thickness.

It is possible to obtain a shading layer 211 which has an aperture whichcorresponds to a cylindrical lens which forms the lens array byperforming a patterning operation for the photosensitive layer byemitting a parallel light which is collimated in 1° to 5° against asurface for forming a lens of the lens array sheet 201 and transcribinga black film (a transcription film of a carbon black) which has 2 μmthickness.

It is observed that it is possible to obtain a perspective angle so asto correspond to the second lens array 207 by using the lens array sheet201 which is obtained in this way and using the first lens array 205 fordispersing a light in a horizontal direction.

Third Embodiment

Furthermore, a third embodiment of the present invention is explainedwith reference to drawings.

FIG. 12 is a view for explaining an example for a structure of atransparent projection screen which relates to a lens array sheetaccording to an example of the present invention.

In a structure for the projection screen which is shown in the abovedrawing, a fresnel lens sheet 390 in which a lens section 392 isdisposed on a surface of a base board 391 near a light emitting sectionand a lens array sheet 380 in which an orthogonal lens section 382 isdisposed on a surface (near light emitting section) of a lightdispersing base board 382 which is formed by dispersing an opticaldispersing agent (particle) is disposed such that mutual lens sections392, 382 should face each other.

For such a transparent resin which is used for the base boards 392, 381,it is possible to use, for example, acrylic resin, polycarbonate resin,polyester resin, polyethylene resin, polyolefin resin, vynil chrorideresin, polyimide resin, a blended product of the above resins, or asheet or a film which is formed by copolymer.

For a member to form the lens sections 392, 382, it is possible to useany member limitlessly as long as it can be used for an optical memberbecause it is a transparent member such as a glass member or a plasticmember. It is preferable to use a plastic member if a manufacturingefficiency is taken into account.

For a plastic member, it is possible to name an acrylic resin such aspolymethyl methacrylate, a polycarbonate, an copolymer of acryl-stylene,a Stylene resin, and a Polyvinyl chloride.

Also, it is preferable to use a radiation curable resin such as anultraviolet-ray curable resin or an electronic beam curable resin for amember for forming the lens sections 392, 382 because it is possible toform a fine pitch.

For such a radiation curable resin, for example, it is possible to use acomposition which is formed by doping a reaction diluting agent, a lightpolymerization starting agent, and an photosensitizer to aurethane(meta)acrylate and/or an epoxy(meta)acrylateoligomer.

For such an urethane(meta)acrylateoligomer, it is not limited inparticular. For example, it is possible to obtain by reacting polyolssuch as an ethyleneglycol, 1,4 butanediol, neopentylglycol,polycaprolactonepolyol, polyesterpolyol, polycarbonatediol, andpoly(tetramethylene glycol) with a polyisocyanate such as hexamethylenediisocyanate, isophorone diisocyanate, toluene diisocyanate, and xylenediisocyanate.

For such an epoxy(meta)acrylateoligomer, it is not limited inparticular. For example, it is possible to obtain by reacting a(meta)acrylic acid with an epoxy resin such as bisphenol A epoxy resin,bisphenol A epoxy resin, phenolnovolac type epocy resin, terminalglycidyl ether of an additional bishenol A propylene oxide, and afluorene epoxy resin.

It is possible to manufacture the orthogonal lens section 382, forexample, by a following manner.

A radiation curable resin is applied on the optical dispersing baseboard 381 which is formed mainly by the above transparent resin underunhardened condition. A molding stamper is compressed on the surface soas to perform a mold pressing operation. Simultaneously, a predeterminedradiation is emitted so as to harden it; thus, a lens section 382 ismolded.

It is possible to manufacture the lens array layer, for example, by afollowing manner.

That is, during manufacturing a molding stamper for molding aconventional lenticular, for example, a cutting section is formed on asurface of a cylindrical cylinder of which surface is made of a copperin a circular direction of the cylinder by using a cutting byte whichhas a round edge shape. Such cutting sections are formed in a pluralityof sections in parallel, it is possible to obtain a stamper forlenticular. Furthermore, if the cutting sections are formed in aplurality of sections in parallel in an orthogonal direction to thecutting section in the circular direction, it is possible to obtain amolding stamper which is used for manufacturing the lens array layer 313of the present invention.

Therefore, it is possible to manufacture the molding stamper formanufacturing the lens section 382 of the present invention by using apre-installed technology easily; thus, the productivity is desirable.

In this way, it is possible to manufacture the lens section 382according to a method which is similar to the method which is used formanufacturing a conventional lenticular.

Two lens array sheets were conventionally used by forming the lenticularsheets for a horizontal direction and a vertical direction so as to usethe above explained orthogonal lens section 382. In the presentinvention, the first lens array and the second lens array which areformed by disposing a plurality of half columnar cylindrical lenses inparallel are disposed on a common surface such that the longitudinaldirections of the cylindrical lenses should be approximately orthogonal.The lens array sheet is provided with a lens array layer which has aunified lens layer. Therefore, the perspective angles in the horizontaldirection and the vertical direction are enlarged by a piece of the lensarray sheet.

It is possible to modify the optical characteristics such as ahorizontal perspective angle and the vertical perspective angleseparately. In a common usage condition, a light distributioncharacteristics in the lens for the horizontal perspective angle(dispersing characteristics which is indicated by a half angle etc.) isdesigned to be large.

The light distribution characteristics is controlled by factors such asa curvature of an arc in a cross section of the unit lens and a cuttingdepth into the unit lens.

An example for a structure in the orthogonal lens section 382 is shownin FIG. 13.

FIG. 13A is a plan view for showing an example for an orthogonal lenssection 382.

A unit lens (horizontal perspective angle enlarging lens) 382H whichforms a first lens array which enlarges the perspective angle in thehorizontal direction has a cylindrical lens shape such that a peaksection of the unit lens is continuous in a longitudinal direction.

The unit lens (vertical perspective angle enlarging lens) 382V whichforms a second lens array for enlarging the perspective angle in thevertical direction is formed such that the peak section of the unit lensis not continuous over the longitudinal direction (horizontaldirection).

In an example in FIG. 13A, in the first lens array, the unit lenses 382Hare disposed in parallel without intervals therebetween. In the secondlens array, the unit lenses 382V are disposed so as to be separated fromeach other. The present invention is not limited to such structures.

FIG. 13B is a plan view for showing other example for an orthogonal lenssection 382.

FIG. 13B shows a structure in which the unit lenses are disposed inparallel so as to be separated from each other together with the firstlens array and the second lens array.

Both the unit lenses 382H, 382V are disposed so as to have a planesection between the unit lenses. As shown in the drawing, the unit lens382V is disposed in a concave section (where the width of the unit lensis narrow) such that a border line which defines a valley section of theunit lens 82H is non-linear and continuous.

As shown in both FIGS. 13A and 13B, the height of the unit lens 382H ishigher than the height of the unit lens 382V (in the molding stamperwhich has a corresponding opposite shape, a valley section is disposeddeeper). Thus, the peak section of the unit lens 382H is continuouslinearly over the longitudinal direction of the cylindrical lens.

The original shape for the cylindrical lens is less deformed in astructure shown in FIG. 13B in which a plain section is provided betweenthe unit lenses and other unit lenses are disposed in a plain section.Therefore, it is possible to anticipate that the optical characteristicswhich correspond to the first lens array and the second lens array aremaintained independently.

Also, there are fewer cutting steps in a manufacturing operation in astructure shown in FIG. 13B; therefore, it is possible to manufacturemore easily than in a structure shown in FIG. 13A.

In the present invention, following modifications are included otherthan the structures shown in FIGS. 13A and 13B.

In the first lens array, the unit lenses 382H are disposed separatelyvia the plain section. In the second lens array, the unit lenses 382Vare disposed without intervals.

The unit lenses are disposed in parallel without intervals both in thefirst lens array and the second lens array.

If a shading layer is formed in a section which corresponds to anon-light condensing section according to the light condensingcharacteristics by the lens array on a plain surface near an oppositelens array in the lens array sheet shown in FIGS. 13A and 13B, such acondition indicates a structure shown in FIG. 14.

That is, a section which corresponds to a peak section of the lens arrayis a light condensing section so as to be a light transmitting section(aperture). Therefore, according to a fact that a peak section of theunit lens (horizontal perspective angle enlarging lens) which forms thefirst lens array is continuous in a longitudinal direction, in a stripeaperture (in the drawing, it is described for a horizontal directiontransmitting section) and the unit lens (vertical perspective angleenlarging lens) 382V which forms the second lens array, according to afact that the peak section of the unit lenses is formed in anon-continuous manner over a length direction (horizontal direction), anapproximate spot aperture (it is described as a horizontal directiontransmitting section in the drawing. Each spot is in a stripe mannerwhich corresponds to a light condensing section in the cylindrical lens)is formed; thus, a shading pattern which is shown in the drawing isformed.

A ratio which is occupied by the shading layer is preferably in a rangeof 30 to 90% for observing a displayed image in a high contrast so as tobe controlled by a light condensing characteristics of the lens array (afocusing condition in a plain surface which is opposite to the lensarray) and a disposition of the unit lenses.

Here, for a case for a lens sheet which has a lens section in a finepitch (high resolution), it is preferable to employ a method such as aself-alignment method in which a position which corresponds to anon-light-condensing section in each lens section is determinedaccurately by using a light-condensing-characteristics of the lenssection itself against a photosensitive resin layer which is formed on asurface which is opposite to the lens on the lens sheet for forming theshading layer.

In order to form a shading layer which has a preferable shading ratiofor the transparent projection screen (it is empirically understoodcommonly that a range such as 60% or greater is desirable for a contrastof the image), a position for condensing (focusing) a light by the lenssection is set preferably inside the photosensitive resin layeraccording to the shading ratio for the pattern to be formed.

For such a self-alignment method, it is possible to name a wet method inwhich a shading pattern is formed after performing a developing processoperation for the exposed photosensitive resin layer and a dry method inwhich the exposed photosensitive resin layer is colored withoutperforming a developing processing operation so as to form the shadingpattern.

In the dry method, a photosensitive adhesive agent is used which has acharacteristics which becomes adhesive according to whether or not it isexposed to a light; thus, it is colored according to whether or not itis adhesive.

Third Example

FIG. 15 is a table for comparing optical characteristics in sampleswhich are prototypes produced by various designs for a screen (examples3-1 to 3-3) in which a lens array sheet of the present invention is usedand a screen (comparative examples 1 and 2) in which a lenticular sheetis used in which conventional cylindrical lens groups are disposed inparallel in a direction (horizontal direction).

In the screen of the comparative example 1, a fresnel lens sheet (whichdoes not have an optical dispersing layer which is formed by opticaldispersing agent for a base member, and haze is 0%) and a lenticularsheet (which is an H lens in which cylindrical lens groups are disposedin parallel in a horizontal direction such that an optical dispersinglayer is provided on the base member, and haze is 80%) are disposed froma projector to therefarther.

In the screen of the comparative example 2, a fresnel lens sheet (whichhas an optical dispersing layer which is formed by optical dispersingagent for a base member, and haze is 60%) and a lenticular sheet (whichis an H lens in which the base member has an optical dispersing layer,and haze is 80%) are disposed from a projector to therefarther.

In the screen of the example 3-1, a fresnel lens sheet (which does nothave an optical dispersing layer which is formed by optical dispersingagent for a base member, and haze is 0%) and a lenticular sheet (whichis an H lens in which cylindrical lens groups are disposed in parallelin horizontal/vertical directions such that an optical dispersing layeris provided on the base member, and haze is 80%) are disposed from aprojector to therefarther.

The structure for the cylindrical lens groups which are disposed inparallel in a vertical direction in the orthogonal lenses is called a Vlens instead of the H lens. In FIGS. 15 and 16, the “lenticular lens(V)” and the “lenticular lens (H)” are itemized separately. These areformed unitarily so as to be described as cross lenticular lenses 1 and2. Here, the cross lenticular lens 1 is designed such that a value ofangle aV should be 10 degrees. Here, the cross lenticular lens 2 isdesigned such that a value of angle aV should be 20 degrees.

In the screen of the example 3-2, a fresnel lens sheet (which has anoptical dispersing layer which is formed by optical dispersing agent fora base member, and haze is 60%) and a lens array sheet (which is anorthogonal lens which has the same optical characteristics as that inthe example 3-1 which has an optical dispersing layer on the basemember, and haze is 80%) are disposed from a projector to therefarther.

In the screen of the example 3-3, a fresnel lens sheet (which has anoptical dispersing layer which is formed by optical dispersing agent fora base member, and haze is 60%) and a lens array sheet (which is anorthogonal lens which does not have the same optical characteristics asthose in the examples 3-1 and 3-2 which have an optical dispersing layeron the base member, and haze is 80%) are disposed from a projector totherefarther.

According to these drawings, it is clearly understood that the samplesaccording to the embodiments have more improved light distributingcharacteristics (which indicates a broadened perspective angle) in thevertical direction.

In the examples 3-1 to 3-3, any of half angle áV (a measured angle inwhich a brightness of an emitted light which is measured orthogonallyfrom a front surface to a lens array sheet is as a half as the halfangle which is measured in an offset manner from the orthogonalcondition) by the V lens in the vertical direction is 35° or greater.

According to the drawing, it is understood that the optical distributioncharacteristics for not only the aV and dV but also βB and γV (measuredangles in which a brightness of an emitted light which are measuredorthogonally from a front surface to a lens array sheet are as ⅓,{fraction (1/10)} respectively which is measured in an offset mannerfrom the orthogonal condition) in the vertical direction are improved bythe V lens function than in comparative examples (lower stages) whichhave more optical dispersing layers.

FIG. 16 is a table for comparing an optical characteristics whichrelates to a contrast in the above examples 3-1 to 3-3 and thecomparative examples 1 and 2.

A difference for the contrast between the embodiments (300 to 330) andthe comparative examples (220, 250) is outstanding in an observationcondition which corresponds to a bright room under condition of 200 Luxor O Lux.

The vertical perspective angle is broadened by the optical dispersinglayer in the comparative example; therefore, it is necessary to usermore amount of optical dispersing agent. Therefore, the contrast isreduced by broadening the perspective angle; thus, a phenomenon occursin which a reappearance characteristics for the image are deteriorated.

Industrial Applicability

As explained above, in the first aspect of the present invention, it ispossible to control an optical distribution characteristics in both thevertical direction and the horizontal direction for the light whichtransmits through the lens array layer. Therefore, it is possible torestrict a material cost and a manufacturing cost with compared to acase in which two layers such as lens array layers are used, or the lenslayers are formed on both surfaces of the base member layer. Also, it ispossible to avoid the optical absorption by the dispersing layer and thereduction of the gain by omitting or simplifying the dispersing layer 8.As a result, it is possible to restrict a white dispersion phenomenonwhich is caused by the dispersing layer so as to realize a high S/Nratio.

In the second aspect of the present invention, it is possible to improvethe S/N ratio by disposing the shading layer; thus, it is possible toprovide an image which has a desirable contrast.

In the third aspect of the present invention, the cross sectional shapeof the cylindrical lens is aspherical; therefore, it is possible toreduce the aberration during a focusing operation and form the incidentlight in a fine pitch.

In the fourth aspect of the present invention, the lens layer in thelens array layer is formed by the radiation curable resin; therefore, itis possible to perform a forming operation in a fine pitch.

In the fifth aspect of the present invention, it is possible to providea transparent screen which has the above effects by combining the lensarray sheet and the fresnel lens which is described in any one of thefirst to fourth aspects.

In the fourth aspect of the present invention, the lens layer in thefresnel lens is formed by the radiation curable resin; therefore, it ispossible to perform a forming operation in a fine pitch.

Also, it is possible to control the optical distribution characteristics(perspective angles) completely independently in the vertical directionand the horizontal direction for the light which transmits through thelens array sheet in the lens array sheet of the present invention bymodifying the lens shapes for the first lens and the second lens. Such afact indicates that it is possible to control the opticalcharacteristics in the screen positively; thus, such a feature has agreat effect for shortening the Research and Development period andreducing the cost.

Also, it is possible to set the perspective angles both in the verticaldirection and the horizontal direction by a piece of the lens sheetdesirably; therefore, there are effects such as 1) it is possible toreduce the cost for the forming operation greatly, 2) it is notnecessary to develop/mix the material member because it is possible toset the amount (effect) of the optical dispersing agent according to aprepared material member, and 3) it is possible to restrict the opticalabsorption (a light amount loss); thus, it is possible to realize abright screen easily.

Also, it is possible to reduce more optical dispersing agent than in aconventional case; therefore, the reflection dispersion of an externallight is restricted; thus, the transparency is enhanced and an opticalabsorption operation in the shading layer increases. Thus, it ispossible to realize an improved S/N ration which has not been realizedin the conventional case.

As explained above, in the present invention, it is possible to controlan optical distribution characteristics in both the vertical directionand the horizontal direction for the light which transmits through thelens array layer. Therefore, it is possible to restrict a material costand a manufacturing cost with compared to a case in which two layerssuch as lens array layers are used, or the lens layers are formed onboth surfaces of the base member layer.

In particular, in a case in which a perspective angle in the screen inthe vertical direction in which a horizontal lencitular in which ashading layer is formed near a observing person is used, if an imagelight is transmitted through other lens element (vertical lenticular)before the image light is incident into the horizontal lenticular, theimage light of which perspective angle is broadened by the other lenselement is blocked (absorbed) by the shading layer in the horizontallenticular. Therefore, it is desirable that the perspective angle shouldbe broadened in a section of the lens element. Thus, the presentinvention is advantageous.

Also, it is possible to avoid the optical absorption by the dispersinglayer and the reduction of the gain by omitting or simplifying thedispersing layer 8. As a result, it is possible to restrict a whitedispersion phenomenon which is caused by the dispersing layer so as torealize a high S/N ratio.

Furthermore, in the present invention, the shape for the cylindricallenses in the unit lenses 382H and 382V are not deteriorated as shown inFIGS. 13A amd 13B. According to this fact, it is understood that it ispossible to maintain each inherent optical characteristics independentlyeven if the optical characteristics for the first lens and the secondlens are designed separately so as to unify both of them; thus, it ispossible to control the perspective angle characteristics (opticaldistribution characteristics) in the horizontal/vertical directioneasily.

In the present invention, a shading pattern (black matrix=BM) is formedaccording to a “self-alignment method” in which a light condensingsection/non-light condensing section forms an aperture section/shadingsection according to a light condensing characteristics in the lensitself so as to realize a high shading ratio; thus, it is advantageousfor improving the contrast.

1. A lens array sheet which is provided with a lens array layer whichhas a unified lens array wherein first lens arrays and second lensarrays which are formed by disposing a plurality of half-cylindricallenses are disposed so as to cross each other orthogonally on a commonplain.
 2. A lens array sheet according to claim 1 wherein the first lensarray is as high as the second lens array.
 3. A lens array sheetaccording to claim 1 wherein the height of the first lens is differentfrom the height of the second lens array.
 4. A lens array sheetaccording to claim 1 wherein shading sections for shading a transmittinglight are provided on a focal plain of the lens array layer.
 5. A lensarray sheet according to claim 1 wherein a cross section of thecylindrical lens is aspherical.
 6. A lens array sheet according to claim1 wherein the lens array layer is formed by a base material layer and alens layer which is disposed on a surface of the lens array layer, andthe lens layer is formed by a radiation curable resin.
 7. A transparentscreen which is provided with a lens array sheet according to claim 1and a fresnel lens.
 8. A transparent screen according to claim 5 whereinthe fresnel lens is formed by a base material layer and a lens layerwhich is formed on a surface of the fresnel lens layer is formed by aradiation curable resin.
 9. A rear-projection display device accordingto claim 7 further comprising the transparent screen.
 10. A lens arraysheet wherein: a first lens array which is formed by half-cylindricallenses in parallel and half-cylindrical lenses which is formed byhalf-cylindrical lenses in parallel are disposed on a same plain suchthat longitudinal directions of the cylindrical lenses are orthogonal;the lens array is provided with a lens array layer which has a unifiedlens layer; and a plurality of cylindrical lenses are disposed so as tohave intervals in parallel in either one of the first lens array or thesecond lens array.
 11. A lens array sheet according to claim 10 whereina valley section in the first valley section and a valley section in thesecond lens array are disposed so as to coincide with each other.
 12. Alens array sheet according to claim 10 wherein: at least the first lensarray of the second lens array has a group of a plurality of cylindricallenses which are disposed without intervals therebetween; and the groupof cylindrical lenses are disposed in parallel.
 13. A lens array sheetaccording to any one of claims 10 to 12 wherein a plurality ofcylindrical lenses are disposed in parallel without intervals in eitherone of the first lens array or the second lens array in which aplurality of cylindrical lenses are disposed in parallel with intervals.14. A transparent screen which is provided with the lens array sheetaccording to any one of claims 10 to
 12. 15. A transparent screenaccording to claim 14 further comprising the lens array sheet and thefresnel lens.
 16. A rear-projection display device according to claim 14further comprising the transparent screen.
 17. A lens array sheetwherein: a first cylindrical lens which is formed by disposing aplurality of half-cylindrical lenses in parallel and a second lens arraywhich is formed by disposing a plurality of half-cylindrical lenses inparallel are disposed on a same plain so as to be orthogonallyapproximately in longitudinal directions of the cylindrical lens in alens array layer which has a unified lens layer; a peak of unit lens inthe first lens array is continuous over the longitudinal direction; andthe second lens array is disposed by forming the unit lenses the peak ofwhich is not continuous over a longitudinal direction between the peaksof the neighboring unit lenses in the first lens array.
 18. A lens arraysheet according to claim 17 wherein at least the first lens array of thesecond lens array is disposed between the unit lenses so as to have aplain section.
 19. A lens array sheet according to claim 17 wherein: thefirst lens array and the second lens array are disposed in parallel soas to have a plain section between the unit lenses; and the unit lens inthe second lens array is disposed in a continuous concave section of aborder line in a non-linear manner which corresponds to a valley sectionof the unit lens in the first lens array.
 20. A lens array sheetaccording to claim 17 wherein the peak of the unit lens in the firstlens array is higher than the peak of the second lens array.
 21. A lensarray sheet according to any one of claims 17-20, wherein a opticaldistribution characteristics (dispersion characteristics) in the unitlens is different between the first lens array and the second lensarray.
 22. A lens array sheet according to claim 17 wherein: the firstlens array is formed by a horizontal lenticular in which a group ofcylindrical lenses are disposed in parallel and the second lens array isformed by a vertical lenticular in which a group of cylindrical lensesare disposed in parallel; a relationship such as optical distributioncharacteristics in the first lens array>optical distributioncharacteristics in the second lens array is effective; a half angle αV(a measured angle in which a brightness of an emitted light which ismeasured orthogonally from a front surface to a lens array sheet is as ahalf as the half angle which is measured in an offset manner from theorthogonal condition) in the second lens array in a vertical directionis not fewer than 10 degree; a perspective angle dV (a measured angle inwhich a brightness of an emitted light which is measured orthogonallyfrom a front surface to a lens array sheet is as a twentieth half as theperspective angle which is measured in an offset manner from theorthogonal condition) in the second lens array in a vertical directionis not fewer than 35 degree.
 23. A lens array sheet according to claim17 wherein: the lens layer of the lens array sheet and an oppositesurface are plain surfaces; and a shading layer is formed on the plainsurface to which a light is not condensed by the lens layer.
 24. A lensarray sheet according to claim 17 wherein a ratio of the shading layeron the plain surface is between 30% and 90%.
 25. A lens array sheetaccording to claim 17 wherein the shading layer is formed by an aperturesection which is continuous in a stripe manner according to the firstlens array and a non-continuous aperture section in an approximate spotmanner according to the second lens array.
 26. A lens array sheetaccording to claim 17 wherein the lens layer which is formed by ahardened product of radiation curable resin is formed on a surface of aplain base material which is formed by a radiation transmittable basematerial.
 27. A transparent projection screen comprising a fresnel lenssheet for emitting an emitted light from a projector in an approximateparallel light and the lens array sheet of claim 17 are disposed near anobserving person.
 28. A transparent projection screen according to claim17 wherein an optical dispersing layer which is formed by dispersing anoptical dispersing particle is formed at least a part of the fresnellens sheet and the lens array sheet.
 29. A projection screen accordingto claim 27 wherein a shading ratio of a black matrix is between 70% to90%.
 30. A lens array sheet according to claims 1, 10 or 17 a lightcondensing surface (focal plane) by the first lens array group and thesecond lens array group are near a plane emitting plane which isopposite to a lens section which is outside of the emitting plane.
 31. Arear-projection display device according to claim 30, further comprisingthe transparent screen.
 32. A rear-projection display device accordingto claim 15, further comprising the transparent screen.
 33. Arear-projection display device according to claim 27, further comprisingthe transparent screen.
 34. A rear-projection display device accordingto claim 28, further comprising the transparent screen.
 35. Arear-projection display device according to claim 29, further comprisingthe transparent screen.